Carriers are utilized in many textile manufacturing operations for the winding of textile yarn thereon and the unwinding of textile yarn therefrom. These yarn carriers come in many configurations utilizing an elongate hollow body having a transverse circular cross-section and defining an outside surface for receiving wound textile yarn thereon and an inside surface for mounting the carrier on a spindle of a textile machine for winding and unwinding of the yarn. These configurations include cones, cylinders, spools, tubes, pirns, etc. Although some of these yarn carriers are generally cylindrical, many are tapered and have widely varying internal and external tapers depending upon the winding and unwinding properties and precision fit requirements for the spindle of the textile machine and depending upon the particular type of yarn and textile manufacturing operation. These yarn carriers have been constructed of impregnated paper, wood, metal and other materials; however, in recent times many of the textile yarn carriers have been molded from plastic materials.
With all these types of carriers for textile yarn, problems to some degree are presented with undesirable sloughing-off or migration of the textile yarn during winding and unwinding and with minimizing the amount of material needed to construct the carrier while retaining desired crush strength of the carrier necessary to withstand the winding forces produced by the yarn on the carrier.
In order to minimize undesirable sloughing-off or migration of the yarn during winding and unwinding of the yarn on these carriers, various abrasive surfaces have been formed on the outside surface of the carrier by knurling or otherwise forming a rough surface. While some of these abrasive surfaces have minimized undesirable sloughing-off or migration of the yarn during winding and unwinding operations, these abrasive surfaces have presented other problems in that some types of yarn snag or are otherwise damaged during the winding or unwinding operations. These problems are particularly acute with cross wound textile yarn packages since the yarn is traversed during the winding operation from one end of the carrier to the other.
While stepped outside configurations producing a generally saw-toothed longitudinal cross-section have been suggested for the outside surface of such textile yarn carriers, the configurations thereof have not been totally successful in minimizing undesirable sloughing or migration of the yarn, particularly for cross-wound textile yarn packages.
Problems have also existed with construction of these types of yarn carriers is to minimize the material utilized for such yarn carriers, particularly molded plastic yarn carriers, while retaining desired crush strength for the carriers against the forces produced by the wound textile yarn. Attempts to minimize the material utilized in such textile yarn carriers have included cutting away or reducing the material in molded plastic carriers from the inside surface of the carrier while retaining longitudinally extending reinforcing ribs or the like to allow the carrier to fit a spindle of a textile yarn processing machine. However, these problems would become more acute when utilizing an outside stepped or saw-toothed configuration inasmuch as material is already removed or eliminated from the inwardly stepped portions of the thickness of the carrier which weaken the crush strength of the carrier.